Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA

Following open-pit coal mining in the Powder River Basin, landscape reconstruction includes the construction of backfill aquifers from overburden waste rock. With overburden disaggregation and the re-introduction of groundwater, the weathering of newly available mineral surfaces and mobilization of...

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Main Authors: Jeff B. Langman, Julianna Martin
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Hydrology
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Online Access:https://www.mdpi.com/2306-5338/12/1/8
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author Jeff B. Langman
Julianna Martin
author_facet Jeff B. Langman
Julianna Martin
author_sort Jeff B. Langman
collection DOAJ
description Following open-pit coal mining in the Powder River Basin, landscape reconstruction includes the construction of backfill aquifers from overburden waste rock. With overburden disaggregation and the re-introduction of groundwater, the weathering of newly available mineral surfaces and mobilization of nanomaterials can impact groundwater quality even when such issues were not previously detected in the overburden’s groundwater. Kinetic columns of Powder River Basin waste rock were used to evaluate backfill construction options—zeolite amendment, and soil amendment, compaction, rinse—that could reduce potential groundwater quality impacts. The leachate from each column was collected twice weekly for 20 weeks. The Eh and pH of the leachate substantially varied during an initial high-weathering period indicative of the traditional weathering of newly exposed mineral surfaces and the weathering and flushing of mobile particles. Correspondingly, select elements, such as arsenic and cadmium, were present in relatively high concentrations during this initial weathering period. Waste rock that was compacted or rinsed produced leachate with less solutes and potential contaminants when compared to the unaltered and zeolite- and soil-amended waste rock. Greater compaction during backfilling is possible but may require additional consideration for connecting the surface drainage network to the surrounding area. Rinsing of the waste rock is a viable construction option because of the temporary storage of the waste rock prior to backfilling but would require leachate collection for contaminant treatment.
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spelling doaj-art-1337809bc2364f6e83926df523eb858e2025-01-24T13:34:53ZengMDPI AGHydrology2306-53382025-01-01121810.3390/hydrology12010008Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USAJeff B. Langman0Julianna Martin1Department of Earth and Spatial Sciences, University of Idaho, Moscow, ID 83844, USADepartment of Earth and Spatial Sciences, University of Idaho, Moscow, ID 83844, USAFollowing open-pit coal mining in the Powder River Basin, landscape reconstruction includes the construction of backfill aquifers from overburden waste rock. With overburden disaggregation and the re-introduction of groundwater, the weathering of newly available mineral surfaces and mobilization of nanomaterials can impact groundwater quality even when such issues were not previously detected in the overburden’s groundwater. Kinetic columns of Powder River Basin waste rock were used to evaluate backfill construction options—zeolite amendment, and soil amendment, compaction, rinse—that could reduce potential groundwater quality impacts. The leachate from each column was collected twice weekly for 20 weeks. The Eh and pH of the leachate substantially varied during an initial high-weathering period indicative of the traditional weathering of newly exposed mineral surfaces and the weathering and flushing of mobile particles. Correspondingly, select elements, such as arsenic and cadmium, were present in relatively high concentrations during this initial weathering period. Waste rock that was compacted or rinsed produced leachate with less solutes and potential contaminants when compared to the unaltered and zeolite- and soil-amended waste rock. Greater compaction during backfilling is possible but may require additional consideration for connecting the surface drainage network to the surrounding area. Rinsing of the waste rock is a viable construction option because of the temporary storage of the waste rock prior to backfilling but would require leachate collection for contaminant treatment.https://www.mdpi.com/2306-5338/12/1/8metal mobilitymining waste rockliberated mineral surfacesconstruction options for backfill aquifer
spellingShingle Jeff B. Langman
Julianna Martin
Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA
Hydrology
metal mobility
mining waste rock
liberated mineral surfaces
construction options for backfill aquifer
title Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA
title_full Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA
title_fullStr Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA
title_full_unstemmed Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA
title_short Kinetic Column Evaluation of Potential Construction Options for Lessening Solute Mobility in Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA
title_sort kinetic column evaluation of potential construction options for lessening solute mobility in backfill aquifers in restored coal mine pits powder river basin usa
topic metal mobility
mining waste rock
liberated mineral surfaces
construction options for backfill aquifer
url https://www.mdpi.com/2306-5338/12/1/8
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